1. Field of the Invention
The present invention relates to a projection system.
2. Description of the Related Art
Hitherto, a projection apparatus, i.e., a projector for projecting an image on a screen has widely been commercialized. In addition, a projection system has been known, which displays projection images respectively projected from a plurality of projection apparatuses onto the same position by superimposing the projection images thereonto, for purposes of enhancing luminance of each of the projection images and stereoscopically displaying the projection images utilizing parallax. Many projectors have an on-screen-display (OSD) function of displaying a menu screen on the projection image with a view to displaying or adjusting operating-conditions.
If projection images are projected by a plurality of projectors onto the same projection plane, when a certain projector projects an image including an OSD screen, a projection image projected by another projector is superimposed on the OSD screen with a result of reduction in visibility of the OSD screen. As a countermeasure against this problem, a technique has been discussed. In the technique, when a certain projector projects an image including an OSD screen, another projector changes the projected image so that the image doesn't reduce the visibility of the OSD screen. According to techniques discussed in, e.g., Japanese Patent No. 3826659 and Japanese Patent Application Laid-Open No. 2002-55669, at least within a range in which the OSD screen is displayed, the projected image is blackened. However, conventional techniques have the following problems. More specifically, the luminance of the OSD screen in the displayed image is reduced to be lower than that of the remaining area of the displayed image, so that the displayed image becomes unnatural. In addition, because only a menu projected by a single projection apparatus can basically be displayed, operating-conditions cannot be set while menus projected by other projectors are referred to.